Subject: [mg110805] Re: overloading a function name in a package? How to query all names?

From: Pierre Albarede <pa.news at free.fr>

Date: Wed, 7 Jul 2010 07:43:01 -0400 (EDT)

References: <i0urgq$6kp$1@smc.vnet.net>

Hi,
On Jul 6, 11:03 am, "Nasser M. Abbasi" <n... at 12000.org> wrote:
> I have package where I overloaded the same function name, defined to
> accept different arguments. as follows:
>
> -------------------
> BeginPackage["foo`"]
>
> boo1::usage="call me as follows: boo1[a,b]"
> boo1::usage="call me as follows: boo1[a]"
>
> Begin["`Private`"]
>
> boo1[a_,b_]:=Module[{},Print["in v1 of boo1"]];
>
> boo1[a_]:=Module[{},Print["in v2 of boo1"]];
>
> End[]
> EndPackage[]
> --------------------------------
>
> Now, I do
>
> <<foo`
>
> And I can call either of them OK
>
> boo1[1,2]
> boo1[1]
>
> But when I do
>
> Names["foo`*"]
>
> It only shows name boo1 once. (I can understand this*)
>
> And when I do
>
> ?foo`*
>
> It only list boo1 once. It seems to show the ::usage of the last one.
> OK. I can understand this.
>
> But, then, is there a way to show the user than I have more than one
> version of the same function name in the package? Without having to look
> into the package file?
>
> I'd like to overload the function name, since I need to call it
> differently sometimes, and I do not want to make up new names of the
> same function, as in booV1[], booV2[], etc... since they all do the same
> logical action, but accept different arguments depending on the options
> needed, and so they all just have the same name, and the correct version
> will be called depending on the arguments used.
>
> Overloading works OK when calling. I am just asking on how to show that
> I have more than one function of the same name in the package, so I know
> how to call each one.
>
> I looked a the docs, but so far, did not see anything. will keep looking.=
...
>
> thanks
> --Nasser
Your description is indeed the normal behaviour of Mathematica.
Actually, Mathematica maintains a tables of rules for every symbol
(function, plain variable, whatever).
Instead of
boo1::usage="call me as follows: boo1[a,b]"
boo1::usage="call me as follows: boo1[a]"
you will write
boo1::usage="call me as follows: boo1[a,b] or boo1[a]"
You can choose to have two names if you like.
A slight detail : there is no interest in wrapping things in Module.
The only local construct you will ever need in functional programming
is
f[x_]:=g[x]
or
With[{x=3},g[x]].
Good luck.